$-9xy - 6xz + 9x + 1 = -3y - 3$ Solve for $x$.
Combine constant terms on the right. $-9xy - 6xz + 9x + {1} = -3y - {3}$ $-9xy - 6xz + 9x = -3y - {4}$ Notice that all the terms on the left-hand side of the equation have $x$ in them. $-9{x}y - 6{x}z + 9{x} = -3y - 4$ Factor out the $x$ ${x} \cdot \left( -9y - 6z + 9 \right) = -3y - 4$ Isolate the $x$ $x \cdot \left( -{9y - 6z + 9} \right) = -3y - 4$ $x = \dfrac{ -3y - 4 }{ -{9y - 6z + 9} }$ We can simplify this by multiplying the top and bottom by $-1$. $x= \dfrac{3y + 4}{9y + 6z - 9}$